take it to a shop and have them retard the timing??
or can you do that anymore, it might be all chips these days, I bought warrenty so I diden't have to worry about it.

Have ford put the computer on it it could be somthing like a sensor or PVC valve.. cheap fix..
not likely either just examples.

 

87 is what is recomended & I haven't had
any problems. That's what I'll use until I put a
superchip in it.

 

Had a 99 SC 4.2 that pinged after about 4k so I started using 89 octane until it could be taken back to the dealer. We were on a trip across Kansas where the wind always blows with a load of about 700 lbs. While I checked out of the motel my wife filled the truck with 87 octane and we had a head wind. Constant ping so I finally set the cruise and let it ping until I could run enough gas out to fill with 93 and mix it. After 50 miles the ping stopped and never happened again for the 2.5 years I had the truck. The dealer said the computer reprogramed itself to eliminate the ping.

I am not saying this is the way to stop the ping just relating what happened to me 3 years ago, because I would have never intentionally ran the truck like that trying to get rid of the ping.

 

Used to use 87 octane but over half year ago switched to mid-grade - 89. I felt that there was an improvement in power; especially in towing or with a heavy load and if I lugged the engine a bit, well (oops)... Considering the cost of the truck, financing, insurance, replacing tires, air filters, oil changes, washing and waxing, stereos, appearance goodies, etc, etc, are you going to worry about a few cents per liter or gallon??? The best performance mod ever!

(87 octane was really designed for low performance engines, like for lawn lowers and chevy's)